Diamond-like carbon coating on injectors.

[wrightpt]

The customer has tons of waste oil. Wants to run b100 biodiesel in his 6.7 Cummins, isx15, and dd15.


To prevent carbon deposits, is it best to have injectors "diamond-like carbon-coated?"

I expressed it is ideal to utilize Viton rubber as gaskets when rebuilding. No rubber gas lines unless Viton.

He said he will take care of timing and software in terms of ignition. Another friend of his has a performance diesel shop.

Many thanks for helping to ensure his b100 transition is a success.

 

[TugboatEng]

Those engines use Bosch injection systems which already utilize DLC and all elastomers in the fuel system are already Viton.

 

[wrightpt]

Excellent info. He should not have an issue converting to biodiesel b100, correct? Assuming the diesel shop tunes appropriately for his specific biodiesel which meets/exceeds national quality standards according to his documentation.

Have u seen a successful transition thus far?

Thank you

 

[TugboatEng]

I am in an area with strict emissions controls. We don't have the option of running non-certified fuels.

 

[wrightpt]

Have you had issues running alternative fuels in marine vessels powered by diesel? Specifically biodiesel?

What would be the main issues engine-wise? If the fuel is stored in a way to prevent water absorption and contamination.

 

[moon161]

I used to run WVO in my benz 240D and I also read up on biodiesel production before deciding I was not an organized enough person to DIY it without making a giant mess, hazmat problem, toxic waste problem, or a big boom. WVO storage, drying and filtration was messy enough.

My source on this was mostly'Biodiesel, basics and beyond'

From being involved in the grease/biodiesel community I learned:
Adverse outcomes are possible but not the rule.
Biodiesel will decompose rubber/EPDM hoses, seals and so on. You need Viton / Viton lined fuel hoses. You can find kits or DIY.
Biodiesel is not shelf stable like diesel
Feedstock and process quality matter
It works better on older motors. Contemporary motors can throw codes for non-standard diesel. Cars & trucks that won't (no fuel quality sensors) are about 20 years or more old now (late 90's I think)
Biodiesel can have a high gel point and get you stuck if you're not careful about it.

Myself, if I got back into it, I would just research blending and do that. 80% WVO / 20% unleaded was what I recall people using.

The big and active fora that were the internet part of the community all seem inactive or gone for the most part.

 

[BrianPetersen]

I've seen too many pictures of sticky gooped-up internals of fuel injection systems on modern-ish diesel engines to ever want to try more than a low blend of biodiesel. With a direct-injection common-rail engine, I think you'll get injector problems (be it clogged, fouled, not spraying properly, or dribbling fuel all the time), and that's if you don't blow up the HPFP first.

Hydrocarbons (mostly) boil when you heat them up. Biodiesel chemically breaks down. It appears that the breakdown temperature is in the vicinity of 275 C, and injector tips will easily see that.

 

[mc5w]

You also need to make sure that your biodiesel has no alcohols or gylcols such as propylene glycol or ethylene glycol. These will degrade Viton. In other words, your fuel system needs to be designed for it if you are using fuel that has ethanol in it. Propylene glycol is sometimes used a s food additive such as to break up large crystals in ice cream so that it is still scoopable when very cold or as a sweetener.

There substance versus seal compatibility charts that you can find on the Internet.

Another consideration is that polyunsaturated vegetable oils react with oxygen to produce dry paint which is a form of room temperature vulcanization. One of my Aunt Barbara's chemistry books explained the basics of oil paint. You might want to hydrogenate the used cooking oil before using it. In oterh words, there are pitfalls to biodeisel.